The present invention relates generally to the field of filters or dams that are utilized to impede flow through curbside storm water drains, of the type often found adjacent to roads or parking lots. In particular, the present invention relates to an improved curb guard filter that may be advantageously applied to a vertical curbside inlet opening.
Curbside drainage systems are designed to manage rain or other liquid runoff resulting from rainfall, liquid spills, etc., that flow onto streets, parking lots, and other proximate structures and areas. A curbside storm drain typically comprises a substantially vertical orifice several inches in height in the side of a sidewalk curb and often has a grated opening disposed in the surface of the road or paved area in front of the curb drain. The runoff may be inherently toxic, or in the case of rainwater runoff, often picks up and carries various pollutants such as soil, rocks, oils, and other contaminants and is therefore potentially harmful to the downstream natural and artificial waterways that the storm drain system empties into.
In view of the potential for drain system contamination, it is often desirable, and sometimes mandated, that curb side drains be blocked or filtered in some manner to prevent or control the entry of contaminants into the drain system. For example, near construction sites or other area likely to be susceptible to toxic substance spillage, flow into the curb drain must be controlled so that undesirable matter, such as for example dirt, oil, debris, etc., does not enter the storm water drainage system.
Examples of devices which have been developed to preclude or to filter the liquid flow through a curb inlet drain include those disclosed in U.S. Pat. No. 6,214,216 to Isaacson, U.S. Pat. No. 5,632,888 to Chinn et al., U.S. Pat. No. 5,403,474 to Emery, U.S. Pat. No. 6,274,036 to Ellis, and U.S. Pat. No. 5,954,952 to Strawser. For example, Isaacson discloses a catch basin insert or sock filter supported within a grated curb inlet storm drain. Adjustable, spring-loaded rods are inserted into loops on the edges of the catch basin filter and utilized to support the filter on the horizontal plane of the storm drain such that the horizontal support does not depend on the downward gravity force of the grate being applied on all four sides of the filter, or else the grate itself is used to secure the sock filter. A portion of the horizontally disposed filter is vertically extended in an L-shaped manner to provide a vertical filter or dam to prevent debris from passing through the curb inlet. In this configuration, the vertical dam is a single sheet supported on its upper end by an adjustable spring-loaded rod. There is however, no provision for securing the vertical dam at its lower end, and the device is clearly not useable where only a curb inlet with no storm drain is present. Thus, it will be relatively easy for the vertical dam to be moved or distorted out of position by the force of inflowing liquids and debris, and undesirable liquid or debris may readily pass around the vertical dam.
Chinn describes an environmental filter comprising an envelope of filter material that is proportioned to receive a storm drain inlet cover or other internal support device and provide filtration over drain catch basin. A vertical roll filter may be combined with the horizontally disposed envelope filter using straps, weights, pins, hooks, or anchors. Although effective in providing a robust barrier to inflowing particulates and debris, Chinn's utilization of a roll filter fails to provide comprehensive sealing of the vertical curb inlet orifice.
Emery discloses a portable curb inlet sediment filter having a box filter frame and a baffle panel defining a filter chamber and an overflow chamber. While providing a stable and comprehensive coverage of the vertical curb inlet orifice, Emery's box filter is unwieldy and, like Chinn's vertical roll filter, does not form a close seal along the mouth of the orifice.
The drain filter disclosed by Ellis is similar in overall structure and functionality to that shown by Isaacson, including a bag disposed over a horizontal drain portion and a debris dam provided at the upper edge of the back sidewall. Unlike Isaacson, the vertical debris dam depicted by Ellis is not a vertically deployed sheet member and instead comprises a porous cylindrical member that covers the face of a curb inlet slot. Like the roll filter and box filter shown by Chinn and Emery, Ellis's porous cylindrical member is not well-suited for forming a tight seal with the vertical curb drain inlet orifice.
Strawser discloses a stormwater catch basin filter assembly comprising a pair of metal frame elements bounding mesh filters, wherein one of the frames is sized to be co-extensive in area with the horizontal storm grate, and the others frame is sized to be co-extensive in area with the vertical curb inlet orifice. Utilizing rigid and non-adjustable frame elements, Strawser's filter assembly, similar to most of the foregoing described filter/dam devices, fails to provide an effective edge seal around a vertical curb inlet orifice.
Although effective for filtering particulates and some contaminants from entering a storm drain system, the foregoing systems are unnecessarily complex and difficult to implement, requiring the heavy cast metal drainage inlets or grates which is problematic for situations requiring quick selective filtration deployment. It can therefore be appreciated that there exists in the art a need for an improved and simplified curb inlet filter device, and one which is modular in design such that the overall length of the curb inlet filter device can be adjusted as required. The present invention addresses such a need.